Imager device with electric connections to electrical device

ABSTRACT

An imager device is disclosed including a first substrate having an array of photo-sensitive elements formed thereon, a first conductive layer formed above the first substrate, a first conductive member extending through the first substrate, the first conductive member being conductively coupled to the first conductive layer, a standoff structure formed above the first substrate, a second conductive layer formed above the standoff structure, the second conductive layer being conductively coupled to the first conductive layer, and an electrically powered device positioned above the standoff structure, the electrically powered device being electrically coupled to the second conductive layer. A method of making an imager device is disclosed including providing a first substrate having a first conductive layer and an array of photosensitive elements formed above the first substrate, forming a conductive member that extends through the first substrate and is conductively coupled to the first conductive layer, forming a standoff structure above the first substrate, forming a patterned conductive layer above the standoff structure, the patterned conductive layer being conductively coupled to the first conductive layer, and conductively coupling an electrically powered device to the patterned conductive layer positioned above the standoff structure.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is generally directed to the field ofmicroelectronic imager devices and methods of manufacturing suchdevices.

2. Description of the Related Art

Microelectronic imagers are used in digital cameras, wireless deviceswith picture capabilities, and many other applications. Cell phones andPersonal Digital Assistants (PDAs), for example, are incorporatingmicroelectronic imagers for capturing and sending pictures. The growthrate of microelectronic imagers has been steadily increasing as theybecome smaller and produce better images with higher pixel counts.

Microelectronic imagers include image sensors that use Charged CoupledDevice (CCD) systems, Complementary Metal-Oxide Semiconductor (CMOS)systems, or other systems. CCD image sensors have been widely used indigital cameras and other applications. CMOS image sensors are alsoquickly becoming very popular because of their relative lower productioncosts, higher yields and smaller sizes. CMOS image sensors can providethese advantages because they are manufactured using technology andequipment developed for fabricating semiconductor devices. CMOS imagesensors, as well as CCD image sensors, are accordingly “packaged” toprotect the delicate components and to provide external electricalcontacts.

FIG. 1 is a schematic view of a conventional microelectronic imager 1with a conventional package. The imager 1 includes a die 10, aninterposer 20 attached to the die 10 and a housing 30 attached to theinterposer 20. The housing 30 surrounds the periphery of the die 10 andhas an opening 32. The imager 1 also includes a transparent cover 40over the die 10.

The die 10 includes an array of image sensors 12 and a plurality of bondpads 14 that are electrically coupled to the array of image sensors 12.The interposer 20 is typically a dielectric fixture having a pluralityof bond pads 22, a plurality of ball pads 24 and traces 26 electricallycoupling bond pads 22 to corresponding ball pads 24. The ball pads 24are arranged in an array for surface mounting the imager 1 to a printedcircuit board or module of another device. The bond pads 14 on the die10 are electrically coupled to the bond pads 22 on the interposer 20 bywire bonds 28 to provide electrical pathways between the bond pads 14and the ball pads 24. The interposer 20 can also be a lead frame orceramic housing.

The imager 1 shown in FIG. 1 also has an electrically powered device 40attached to the housing 30. The electrically powered device 30 mayperform a variety of functions, e.g., an electrically powered opticsunit, etc. Typically, electrical connections to such an electricallypowered device 40 are provided by means of conductive straps or traces42 that are bonded to external pads 44, 46 formed on the interposer 20and the electrically powered device 40. An insulating layer 43 may alsobe provided. Such electrical connections to an electrically powereddevice 40 are time-consuming to manufacture, and are susceptible todamage during use.

The present invention is directed to a device and various methods thatmay solve, or at least reduce, some or all of the aforementionedproblems.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be understood by reference to the followingdescription taken in conjunction with the accompanying drawings, inwhich like reference numerals identify like elements, and in which:

FIG. 1 is a schematic depiction of an illustrative prior art imagerdevice;

FIG. 2 is a sectional view of a schematically depicted imager device inaccordance with one illustrative aspect of the present invention in aninitial stage of fabrication;

FIG. 3 depicts the formation of a layer of conductive material above thestructure depicted in FIG. 2;

FIG. 4 depicts the formation of a masking layer above the structuredepicted in FIG. 3;

FIG. 5 depicts the structure shown in FIG. 4 after the masking layer hasbeen patterned to form a patterned masking layer;

FIG. 6 depicts the structure shown in FIG. 5 after the conductive layerhas been patterned;

FIG. 7 depicts an electrically powered component positioned above andelectrically coupled to the structure shown in FIG. 6; and

FIG. 8 depicts another illustrative embodiment of an electricallypowered device positioned above the imager device.

While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof have been shown by wayof example in the drawings and are herein described in detail. It shouldbe understood, however, that the description herein of specificembodiments is not intended to limit the invention to the particularforms disclosed, but on the contrary, the intention is to cover allmodifications, equivalents, and alternatives falling within the spiritand scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

Illustrative embodiments of the invention are described below. In theinterest of clarity, not all features of an actual implementation aredescribed in this specification. It will of course be appreciated thatin the development of any such actual embodiment, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which will vary from one implementation toanother. Moreover, it will be appreciated that such a development effortmight be complex and time-consuming, but would nevertheless be a routineundertaking for those of ordinary skill in the art having the benefit ofthis disclosure.

The present invention will now be described with reference to theattached figures. For purposes of clarity and explanation, the relativesizes of the various features depicted in the drawings may beexaggerated or reduced as compared to the actual size of those featuresor structures. Nevertheless, the attached drawings are included todescribe and explain illustrative examples of the present invention. Thewords and phrases used herein should be understood and interpreted tohave a meaning consistent with the understanding of those words andphrases by those skilled in the relevant art. No special definition of aterm or phrase, i.e., a definition that is different from the ordinaryand customary meaning as under-stood by those skilled in the art, isintended to be implied by consistent usage of the term or phrase herein.To the extent that a term or phrase is intended to have a specialmeaning, i.e., a meaning other than that understood by skilled artisans,such a special definition will be explicitly set forth in thespecification in a definitional manner that directly and unequivocallyprovides the special definition for the term or phrase.

FIG. 2 depicts a plurality of illustrative CMOS imager devices 100formed on a substrate 112. The substrate 112 may be any of a variety ofmaterials, e.g., silicon, silicon germanium, an SOI structure, etc. Theimager devices 100 may be formed in accordance with processingtechniques that are well known to those skilled in the art. The imagerdevice 100 typically comprises an array of photosensitive elements 114,internal circuitry 116 and bond pads 118. The bond pads 118 are adaptedto be electrically coupled to another structure, such as a printedcircuit board (not shown).

A plurality of standoff structures 120 are formed above the substrate112. The standoff structures 120 may be formed by a variety of knowntechniques, and they may be made from a variety of materials, such assilicon, silicon dioxide, polymer, glass, etc. The size andconfiguration of the standoff structures 120 may vary depending upon theparticular application.

A conductive layer 119 is formed above the substrate 112. The conductivelayer 119 may be comprised of a variety of materials, e.g., aluminum,titanium, copper, nickel, etc. The conductive layer 119 may berepresentative of a layer that covers substantially the entire substrate112 or a conductive trace that is part of a patterned conductive layer.The conductive layer 119 may have a thickness ranging from approximately100-300 Å up to several micrometers, and it may be formed by performinga variety of known deposition techniques, e.g., a sputter depositionprocess, a plating process, etc.

Also depicted in FIG. 2 are a plurality of conductive members 122 thatextend through the substrate 112. Such conductive members 122 aresometimes referred to as through-wafer interconnects. These conductivemembers 122 may be formed using known techniques and materials. Theconductive members 122 conductively engage the conductive layer 119. Thesize and configuration of the conductive members 122 may vary dependingupon the particular application.

Next, as shown in FIG. 3, in one illustrative embodiment, a layer ofconductive material 124 is deposited on the structure shown in FIG. 2.The layer of conductive material 124 may be comprised of any of avariety of conductive materials, e.g., platinum, gold,titanium-aluminum, copper, copper-nickel, etc., and its thickness mayvary from approximately 100-20,000 Å depending on the particularapplication. The layer of conductive material 124 may be formed byperforming a variety of known deposition processes, e.g., a physical orchemical vapor deposition process, sputtering, a plating process, etc.In one particularly illustrative embodiment, the layer of conductivematerial 124 is a layer of titanium-aluminum having a thickness ofapproximately 10,000-20,000 Å that is formed by a physical vapordeposition process.

Then, as shown in FIG. 4, a masking layer 126 is formed above the layerof conductive material 124. The masking layer 126 may be made from avariety of materials and it may be formed by a variety of processes. Inone illustrative embodiment, the masking layer 126 is a layer ofelectrophoretic resist material that may be formed using a bath-likeplating process. In other embodiments, the masking layer 126 may be atraditional photoresist material may be formed by traditionalspin-coating techniques.

As shown in FIG. 5, the masking layer 126 is patterned to thereby exposeportions of the underlying layer of conductive material 124. The maskinglayer 126 may be patterned using a variety of techniques, which may varydepending on the materials used for the masking layer 26. In the casewhere the masking layer 26 is comprised of a traditional photo-resist orelectrophoretic resist, traditional exposure and development processesmay be used to pattern the masking layer 26.

Thereafter, as shown in FIG. 6, one or more etching processes 121 may beperformed to remove the exposed portions of the layer of conductivematerial 124. A variety of etching techniques and processes may beperformed to remove the exposed portions of the conductive layer ofmaterial 124. For example, an anisotropic plasma enhanced etchingprocess may be performed to pattern the layer of conductive material124. The patterned masking layer 126 may then be removed or strippedusing a traditional ashing process or a dilute acid bath. Alternatively,a wet etching process may be used.

Next, as shown in FIG. 7, a substrate 130 comprised of a plurality ofelectrically powered devices 132 is positioned above and secured to thedevice. A conductive layer 134 is formed on the bottom surface 136 ofthe substrate 130. The conductive layer 134 may be representative of alayer that covers substantially the entire substrate 130 or a conductivetrace that is part of a patterned conductive layer. The conductive layer134 is conductively coupled to the patterned conductive layer 124 by avariety of known techniques, e.g., a conductive adhesive material. Asthus configured, a conductive path comprising the conductive member 122(in the substrate 112), the conductive layer 119, the patternedconductive layer 124 (above the standoff 120) and the conductive traceor layer 134 is established. Electrical power may be supplied to theelectrically powered devices 132 via this conductive path. In oneillustrative example, the electrically powered devices 132 areelectrically powered optical devices, e.g., an electrically poweredlens. In other embodiments, the electrically powered devices 132 maysimply be an adjustable aperture, filter or light source. Thus, theelectrically powered devices 132 are schematic in nature in that theyreflect any electrically powered device or structure that may affect thequality, quantity or characteristic of light intended to be projectedonto or received by the imaging devices 100.

The substrate 130 may be comprised of a variety of materials. In somecases, the substrate 130 may be comprised of glass or other materialthat allows the transmission of light to the imaging device 100. Theexact nature and properties of the substrate 130 may vary depending onthe particular application.

FIG. 8 depicts an alternative embodiment of the present inventionwherein a conductive path may be established through the substrate 130to provide electrical power to schematically depicted electricallypowered devices 140A and 140B positioned above the substrate 130. Forexample, in one embodiment, the electrically powered devices 140A, 140Bmay be an electrically powered lens. In one embodiment, illustrativeconductive members 122A, e.g., through-wafer interconnects, may beformed in the substrate 130 using traditional techniques. The size andshape of the conductive members 122A may vary depending upon theparticular application.

Thereafter, with respect to the imager device 100 on the left side ofFIG. 8, a conductive layer 125 may be formed above the surface 131 ofthe substrate 130. The conductive layer 125 may be representative of alayer that covers substantially the entire substrate 130 or a conductivetrace that is part of a patterned conductive layer. The schematicallydepicted electrically powered device 140A may be conductively coupled tothe conductive layer 125 using a variety of known techniques, e.g., aconductive adhesive material. The right side of FIG. 8 depicts analternative arrangement wherein bond pads 137 are formed on the surface131 of the substrate 130 and thereby conductively coupled to theconductive members 122A. Bond pads 139 are also formed on theelectrically powered device 140B. Traditional wire bonds 141 areemployed to conductively coupled the pads 137, 139 to one another.

At some desired point in the manufacturing process, the individualdevices 100 may be cut along the illustrative cut lines 150 to separatethe individual integrated circuit devices. At that point, the separateddevices may be packaged using traditional techniques.

As will be recognized by those skilled in the art after a completereading of the present application, the present invention provides anovel way to provide electrical power to an electrically powered devicepositioned above the imager device 100. For example, where the substrate130 comprises an electrically powered focus device, such as theelectrically powered lens 132 depicted in FIG. 7, the present inventionallows electrical power to be supplied to the lens 132 without the needfor cumbersome and problematic bonding wire. More specifically, in theillustrative embodiment depicted in FIG. 7, the conductive path isdefined by the conductive member 122, the conductive layer 119, theconductive layer portion 124 and the conductive trace or layer 134.

The present invention may also be employed to supply electrical power toany of a variety of different electrically powered devices that arepositioned above (not necessarily over) the imager device 100. FIG. 8illustratively depicts such a situation wherein the substrate 130 is aprotective glass cover. Additional standoffs may be provided ifrequired. Conductive members 122A may be formed through the substrate130 to thereby extend the conductive path vertically to a schematicallydepicted electrical component or device 140A, 140B. The substrate 130depicted in FIG. 7 with its associated components may also be consideredto be one type of an electrical component or device.

The particular embodiments disclosed above are illustrative only, as theinvention may be modified and practiced in different but equivalentmanners apparent to those skilled in the art having the benefit of theteachings herein. For example, the process steps set forth above may beperformed in a different order. Furthermore, no limitations are intendedto the details of construction or design herein shown, other than asdescribed in the claims below. It is therefore evident that theparticular embodiments disclosed above may be altered or modified andall such variations are considered within the scope and spirit of theinvention. Accordingly, the protection sought herein is as set forth inthe claims below.

1-23. (canceled)
 24. An imager device, comprising: a first substratecomprising an array of photosensitive elements formed thereon; a firstconductive layer formed above the first substrate; a first conductivemember extending through the first substrate, the first conductivemember being conductively coupled to the first conductive layer; astandoff structure formed above the first substrate; a second conductivelayer formed above the standoff structure, the second conductive layerbeing conductively coupled to the first conductive layer; anelectrically powered device positioned above the first substrate; and asecond substrate positioned above the standoff structure, the secondsubstrate having a second conductive member extending through the secondsubstrate, the second conductive member being conductively coupled tothe second conductive layer and the electrically powered device.
 25. Thedevice of claim 24, wherein the first conductive layer is formed on asurface of the first substrate.
 26. The device of claim 24, wherein thefirst conductive member is a through-wafer interconnect structure. 27.The device of claim 24, wherein the second conductive member is athrough-wafer interconnect structure.
 28. The device of claim 24,wherein the standoff structure is positioned under the second conductivemember.
 29. The device of claim 24, wherein the second conductive layeris formed on a surface of the standoff structure.
 30. The device ofclaim 24, wherein the electrically powered device comprises at least oneof an electrically powered lens, an electrically powered aperture, anelectrically powered filter and an electrically powered light.
 31. Thedevice of claim 24, further comprising a third conductive layer formedon the second substrate, the third conductive layer being conductivelycoupled to the electrically powered device and the second conductivemember extending through the second substrate.
 32. The device of claim24, further comprising a bond pad formed on a surface of the secondsubstrate, the bond pad being conductively coupled to the secondconductive member.
 33. An imager device, comprising: a first substratecomprising an array of photosensitive elements; a first conductive layerformed on the first substrate; a first conductive member extendingthrough the first substrate, the first conductive member beingconductively coupled to the first conductive layer; a standoff structureformed above the first conductive member; a second conductive layerformed above the standoff structure, the second conductive layer beingconductively coupled to the first conductive layer; and an electricallypowered device positioned above the standoff structure, the electricallypowered device comprising a second substrate having a second conductivemember extending through the second substrate, the second conductivemember being positioned above the standoff structure and beingconductively coupled to the second conductive layer.
 34. The device ofclaim 33, wherein the first conductive member is a through-waferinterconnect structure.
 35. The device of claim 33, wherein the secondconductive member is a through-wafer interconnect structure.
 36. Thedevice of claim 33, wherein the second conductive layer is formed on asurface of the standoff structure.
 37. The device of claim 33, furthercomprising a third conductive layer formed on the second substrate, thethird conductive layer being conductively coupled to the electricallypowered device and the second conductive member extending through thesecond substrate. 38-53. (canceled)